Answered by Shaykh Faraz Rabbani
In the Hanafi madhhab, if the Imam needs to pray sitting down due to illness, does the follower pray sitting down as well or do they pray as they normally would?
Answer:
Walaikum assalam wa rahmatullah,
I pray this finds you in the best of health and spirits.
It is valid to pray behind an imam who is sitting down–if they are actually prostrating on the ground itself. In such a case, the followers would pray standing.
However, it is not valid to pray behind an imam who is praying merely with head movements. (Shurunbulali, Maraqi al-Falah; Ala’ al-Din Abidin, al-Hadiyya al-Ala’iyya)
And Allah alone gives success.
Faraz Rabbani